scholarly journals Freeze-Thaw Performance and Moisture-Induced Damage Resistance of Base Course Stabilized with Slow Setting Bitumen Emulsion-Portland Cement Additives

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Mojtaba Shojaei Baghini ◽  
Amiruddin Ismail
Keyword(s):  
Portland Cement ◽  
Soil Aggregates ◽  
Moisture Damage ◽  
Engineering Properties ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Weight Losses ◽  
Bitumen Emulsion ◽  
Geotechnical Characteristics

Freeze-thaw (FT) cycles and moisture susceptibility are important factors influencing the geotechnical characteristics of soil-aggregates. Given the lack of published information on the behavior of cement-bitumen emulsion-treated base (CBETB) under environmental conditions, especially freezing and thawing, this study investigated the effects of these additives on the CBETB performance. The primary goal was to evaluate the resistance of CBETB to moisture damage by performing FT, Marshall conditioning, and AASHTO T-283 tests and to evaluate the long-term stripping susceptibility of CBETB while also predicting the liquid antistripping additives to assess the mixture’s durability and workability. Specimens were stabilized with Portland cement (0%–6%), bitumen emulsion (0%–5%), and Portland cement-bitumen emulsion mixtures and cured for 7 days, and their short- and long-term performances were studied. Evaluation results of both the Marshall stability ratio and the tensile strength ratio show that the additions of additives increase the resistance of the mixtures to moisture damage. Results of durability tests performed for determining the resistance of compacted specimens to repeated FT cycles indicate that the specimen with the 4% cement-3% bitumen emulsion mixture significantly improves water absorption, volume changes, and weight losses. This indicates the effectiveness of this additive as a road base stabilizer with excellent engineering properties for cold regions.

Evaluation of Durability and Permanent Deformation of Modified Road Base Construction Using Rovene® 4045 and Portland Cement Additives

2015 ◽  
Vol 1089 ◽  
pp. 228-234
Author(s):  
Mojtaba Shojaei Baghini ◽  
Amiruddin Ismail ◽  
Mohamad Rehan bin Karim
Keyword(s):  
Portland Cement ◽  
Permanent Deformation ◽  
Engineering Properties ◽  
Weight Changes ◽  
Permanent Strain ◽  
Road Base ◽  
Strain Behaviour ◽  
Wheel Tracking ◽  
Styrene Butadiene

Due to lack of previous study on applying polymer additives in road base construction, this research presents experimental results on the improvement of long-term road base performance by the addition of carboxylated styrene–butadiene emulsion (Rovene® 4045) and Portland cement. The specimens stabilized with Portland cement (0–6%) and Rovene® 4045 (5–10%) and then subjected to different stress sequences to study the wetting and drying (WD) and wheel tracking (WT) tests on the 7-day-cured specimens. Results of tests conducted to assess the specimens’ resistance to WD cycling showed that the addition of a 4% Portland cement–7% Rovene® 4045 mixture resulted in reductions of 86.99% in water absorption, volume changes of 88.55%, and weight changes of 92.84% relative to a sample with only 4% cement after 12 WD cycles. The permanent strain behaviour of the samples was assessed by the WT test. The results of WT test showed that the permanent deformation characteristics of the mixture were considerably improved by utilization of Rovene® 4045 modification, which resulted in reductions of 218.9% at 25 oC, and 356.8% at 50 oC in permanent strain of the mixture respectively. Therefore, this research nominates a new polymer additive having outstanding engineering properties and environmental friendly.

Influence of Nanoclay on Concrete Subjected to Freeze-Thaw Cycles and Bond Behavior between Rebar and Concrete

2016 ◽  
Vol 711 ◽  
pp. 256-262 ◽  
Author(s):  
Ying Fang Fan ◽  
Shi Yi Zhang ◽  
Surendra P. Shah
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Portland Cement Concrete ◽  
Freezing And Thawing ◽  
Bond Slip ◽  
Bond Behavior ◽  
Freeze Thaw ◽  
Pullout Tests ◽  
Cement Based Materials ◽  
Before And After

This paper explores the effects of nanokaolinite clay (NKC) on the behavior of cement-based materials concrete. The resistance of NKC modified cement-based materials to freezing-thaw cycles and the corrosion processes of rebar embedded in the concrete were investigated. Ordinary Portland cement was partially substituted with NKC in ratios of 0%, 1%, 3%, and 5% by weight. The Rapid Freeze-Thaw Cabinet was used to measure the resistance of ordinary Portland cement concrete and concrete with clay to deterioration caused by repeated cycles of freezing and thawing, compressive strength were measured at regular intervals. The corrosion conditions of the rebar embedded in the concrete were studied by an electrochemical accelerated penetration system, pullout tests were performed to assess the bond properties including bond-slip curve, ultimate bond strength between concrete and rebar before and after corrosion. It is revealed that the introduction of NKC improves the freeze-thaw resistivity values and bond behavior in the concrete specimens compared to the control concrete; the corrosion of the rebar embedded in the concrete is impeded efficiently.

scholarly journals Effects of Long-Term Repeated Freeze-Thaw Cycles on the Engineering Properties of Compound Solidified/Stabilized Pb-Contaminated Soil: Deterioration Characteristics and Mechanisms

2020 ◽  
Vol 17 (5) ◽  
pp. 1798 ◽  
Author(s):  
Zhongping Yang ◽  
Xuyong Li ◽  
Denghua Li ◽  
Yao Wang ◽  
Xinrong Liu
Keyword(s):  
Contaminated Soils ◽  
Permeability Coefficient ◽  
Unconfined Compressive Strength ◽  
Soil Structure ◽  
Ct Scanning ◽  
Engineering Properties ◽  
Freeze Thaw ◽  
Pollution Levels ◽  
Deterioration Characteristics

The effects of long-term repeated freeze-thaw cycles and pollution levels on the engineering properties (qu, E50, φ, c, and k) of Pb-contaminated soils were investigated in various laboratory tests. These soils were solidified/stabilized (S/S) with three types of cement-based combined binders (C2.5S5F5, C5S2.5F2.5, and C5S5, cement, lime, and fly ash, mixed in different proportions; these materials are widely used in S/S technology). The strength and permeability coefficient of compound solidified/stabilized Pb-contaminated soils (Pb-CSCSs) were determined based on measurements of unconfined compressive strength (UCS), direct shear, and permeability. CT scanning, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) tests were employed to analyse the deterioration mechanisms under various repetitions of freeze-thaw cycles. The results showed that, under repeated freeze-thaw cycles, the engineering properties of Pb-CSCSs all degraded to varying degrees, though degradation tended to stabilise after 30 days of freeze-thaw cycles. The study also found that the pollutants obstruct hydration and other favourable reactions within the soil structure (such as ion exchanges and agglomerations and pozzolanic reactions). The activation of hydration reactions and the rearrangement of soil particles by freeze-thaw cycles thus caused the engineering properties to fluctuate, and soils exhibited different deterioration characteristics with changes in Pb2+ content.

Mechanisms leading to enhanced soil nitrous oxide fluxes induced by freeze–thaw cycles

2013 ◽  
Vol 93 (4) ◽  
pp. 401-414 ◽  
Author(s):  
Neil Risk ◽  
David Snider ◽  
Claudia Wagner-Riddle
Keyword(s):  
Nitrous Oxide ◽  
De Novo ◽  
Greenhouse Gas Emission ◽  
Soil Aggregates ◽  
Soil Conditions ◽  
Natural Environments ◽  
Freezing And Thawing ◽  
Surface Layers ◽  
Freeze Thaw ◽  
Thaw Cycle

Risk, N., Snider, D. and Wagner-Riddle, C. 2013. Mechanisms leading to enhanced soil nitrous oxide fluxes induced by freeze–thaw cycles. Can. J. Soil Sci. 93: 401–414. The freezing and thawing of soil in cold climates often produces large emissions of nitrous oxide (N2O) that may contribute significantly to a soil's annual greenhouse gas emission budget. This review summarizes the state of knowledge of the physical and biological mechanisms that drive heightened N2O emissions at spring melt. Most studies of freeze–thaw N2O emissions have concluded that denitrification is the dominant process responsible for the large thaw fluxes. Soil moisture, availability of carbon and nitrogen substrates, and freeze temperature and duration are the major factors identified as controlling freeze–thaw cycle (FTC) N2O emissions. Two mechanisms are proposed to lead to enhanced N2O emissions at thaw: (1) the physical release of N2O that is produced throughout the winter and trapped under frozen surface layers and/or within nutrient-rich water films in the frozen layers, and (2) the emission of newly produced (de novo) N2O at the onset of thaw, which is stimulated by increased biological activity and changes in physical and chemical soil conditions. Early studies implicated the physical release of N2O from subsurface soil layers as the main mechanism contributing to spring thaw emissions, but most current studies do not support this hypothesis. Mounting evidence suggests that most of the emitted N2O is produced de novo. This may be fueled by newly available denitrification substrates that are liberated from dead microbes, fine roots, and/or the disintegration of soil aggregates. The release of N2O trapped in shallow surface layers may represent a small, but important contribution of the total emissions. Application of new techniques to study microbial communities in their natural environments, such as metagenomics and stable isotope studies, have the potential to enhance our understanding of the soil N cycle and its linkages to FTC N2O emissions. Future field studies of N2O emissions ought to quantify both overwinter accumulation/release and the de novo production of N2O so that the contribution of each mechanism to the annual emission budget is known.

scholarly journals Petrographic and Geotechnical Characteristics of Carbonate Aggregates from Poland and Their Correlation with the Design of Road Surface Structures

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2034
Author(s):  
Jerzy Trzciński ◽  
Emilia Wójcik ◽  
Mateusz Marszałek ◽  
Paweł Łukaszewski ◽  
Marek Krajewski ◽  
...  
Keyword(s):  
Road Surface ◽  
Surface Structures ◽  
Engineering Properties ◽  
Geological Engineering ◽  
Functional Relationships ◽  
Road Design ◽  
Geotechnical Characteristics ◽  
Design Calculations ◽  
Building Engineering ◽  
Design And Construction

The paper presents the basic problem related with practical application of carbonate rocks in construction: are carbonate aggregates produced from such rocks favorable for building engineering, particularly for road design and construction? To resolve this problem, (1) the geological-engineering properties of aggregates are presented, (2) the correlation between petrographic and engineering parameters is shown, and (3) a strict correlation between the geological-engineering properties and the freezing-thawing and crushing resistance is recognized. This knowledge has allowed to assess the usefulness of asphalt concrete (AC) made from dolomite and limestone aggregates in the design and construction of road surface structures. The petrography was characterized using optical microscopy and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscope (EDS). Engineering properties were determined in accordance with European and Polish norms and guidelines. Statistical and design calculations were performed using dedicated software. The petrographic properties, and selected physical and mechanical parameters of the aggregates, were tested to show their influence on the freezing–thawing and crushing resistance. Strong functional relationships between the water adsorption, and the freezing–thawing and crushing resistance have been observed. Aggregate strength decreased after saturation with increasing concentrations of salt solutions. Calculations of AC fatigue durability and deformation allow for reducing the thickness of the road surface structure by about 20% in comparison to normative solutions. This conclusion has impact on the economy of road design and construction, and allows for a rational utilization of rock resources, which contributes to sustainable development of the construction industry.

scholarly journals Strength and Microscopic Damage Mechanism of Yellow Sandstone with Holes under Freezing and Thawing

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Huren Rong ◽  
Jingyu Gu ◽  
Miren Rong ◽  
Hong Liu ◽  
Jiayao Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Power Function ◽  
Damage Mechanism ◽  
Uniaxial Compression Test ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Microscopic Damage

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.

Review of Strength and Failure Criteria for Concrete After Freeze-Thaw Damage

2012 ◽  
Vol 253-255 ◽  
pp. 456-461
Author(s):  
Yan Fu Qin ◽  
Bin Tian ◽  
Gang Xu ◽  
Xiao Chun Lu
Keyword(s):  
Normal State ◽  
Concrete Strength ◽  
Failure Criteria ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Normal Concrete ◽  
Strength Criteria ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Concrete Failure

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage，this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.

Geothermal modeling of soil or mine tailings with concurrent freezing and deposition

1998 ◽  
Vol 35 (2) ◽  
pp. 234-250 ◽  
Author(s):  
JF (Derick) Nixon ◽  
Nick Holl
Keyword(s):  
Snow Cover ◽  
Mine Tailings ◽  
Frozen Soil ◽  
Freezing And Thawing ◽  
Frozen Ground ◽  
Geothermal Model ◽  
Winter Time ◽  
Upper Boundary ◽  
Good Agreement

A geothermal model is described that simulates simultaneous deposition, freezing, and thawing of mine tailings or sequentially placed layers of embankment soil. When layers of soil or mine tailings are placed during winter subfreezing conditions, frozen layers are formed in the soil profile that may persist with time. The following summer, warmer soil placement may not be sufficient to thaw out layers from the preceding winter. Remnant frozen soil layers may persist for many years or decades. The analysis is unique, as it involves a moving upper boundary and different surface snow cover functions applied in winter time. The model is calibrated based on two uranium mines in northern Saskatchewan. The Rabbit Lake scenario involves tailings growth to a height of 120 m over a period of 24 years. At Key Lake, tailings increase in height at a rate of 1.3 m/year. Good agreement between the observed position of frozen layers and those predicted by the model is obtained. Long-term predictions indicate that from 80 to 200 years would be required to thaw out the frozen layers formed during placement, assuming 1992 placement conditions continue. Deposition rates of 1.5-3 m/year give the largest amounts of frozen ground. The amount of frozen ground is sensitive to the assumed snow cover function during winter.Key words: geothermal, model, tailings, freezing, deposition.

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